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   1 /*
   2  * truncate.c
   3  *
   4  * PURPOSE
   5  *      Truncate handling routines for the OSTA-UDF(tm) filesystem.
   6  *
   7  * COPYRIGHT
   8  *      This file is distributed under the terms of the GNU General Public
   9  *      License (GPL). Copies of the GPL can be obtained from:
  10  *              ftp://prep.ai.mit.edu/pub/gnu/GPL
  11  *      Each contributing author retains all rights to their own work.
  12  *
  13  *  (C) 1999-2004 Ben Fennema
  14  *  (C) 1999 Stelias Computing Inc
  15  *
  16  * HISTORY
  17  *
  18  *  02/24/99 blf  Created.
  19  *
  20  */
  21
  22 #include "udfdecl.h"
  23 #include <linux/fs.h>
  24 #include <linux/mm.h>
  25 #include <linux/udf_fs.h>
  26 #include <linux/buffer_head.h>
  27
  28 #include "udf_i.h"
  29 #include "udf_sb.h"
  30
  31 static void extent_trunc(struct inode *inode, struct extent_position *epos,
  32                          kernel_lb_addr eloc, int8_t etype, uint32_t elen,
  33                          uint32_t nelen)
  34 {
  35         kernel_lb_addr neloc = {};
  36         int last_block = (elen + inode->i_sb->s_blocksize - 1) >>
  37                 inode->i_sb->s_blocksize_bits;
  38         int first_block = (nelen + inode->i_sb->s_blocksize - 1) >>
  39                 inode->i_sb->s_blocksize_bits;
  40
  41         if (nelen) {
  42                 if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) {
  43                         udf_free_blocks(inode->i_sb, inode, eloc, 0,
  44                                         last_block);
  45                         etype = (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30);
  46                 } else
  47                         neloc = eloc;
  48                 nelen = (etype << 30) | nelen;
  49         }
  50
  51         if (elen != nelen) {
  52                 udf_write_aext(inode, epos, neloc, nelen, 0);
  53                 if (last_block - first_block > 0) {
  54                         if (etype == (EXT_RECORDED_ALLOCATED >> 30))
  55                                 mark_inode_dirty(inode);
  56
  57                         if (etype != (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30))
  58                                 udf_free_blocks(inode->i_sb, inode, eloc,
  59                                                 first_block,
  60                                                 last_block - first_block);
  61                 }
  62         }
  63 }
  64
  65 /*
  66  * Truncate the last extent to match i_size. This function assumes
  67  * that preallocation extent is already truncated.
  68  */
  69 void udf_truncate_tail_extent(struct inode *inode)
  70 {
  71         struct extent_position epos = {};
  72         kernel_lb_addr eloc;
  73         uint32_t elen, nelen;
  74         uint64_t lbcount = 0;
  75         int8_t etype = -1, netype;
  76         int adsize;
  77
  78         if (UDF_I(inode)->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB ||
  79             inode->i_size == UDF_I(inode)->i_lenExtents)
  80                 return;
  81         /* Are we going to delete the file anyway? */
  82         if (inode->i_nlink == 0)
  83                 return;
  84
  85         if (UDF_I(inode)->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
  86                 adsize = sizeof(short_ad);
  87         else if (UDF_I(inode)->i_alloc_type == ICBTAG_FLAG_AD_LONG)
  88                 adsize = sizeof(long_ad);
  89         else
  90                 BUG();
  91
  92         /* Find the last extent in the file */
  93         while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 1)) != -1) {
  94                 etype = netype;
  95                 lbcount += elen;
  96                 if (lbcount > inode->i_size) {
  97                         if (lbcount - inode->i_size >= inode->i_sb->s_blocksize)
  98                                 printk(KERN_WARNING
  99                                        "udf_truncate_tail_extent(): Too long "
 100                                        "extent after EOF in inode %u: i_size: "
 101                                        "%Ld lbcount: %Ld extent %u+%u\n",
 102                                        (unsigned)inode->i_ino,
 103                                        (long long)inode->i_size,
 104                                        (long long)lbcount,
 105                                        (unsigned)eloc.logicalBlockNum,
 106                                        (unsigned)elen);
 107                         nelen = elen - (lbcount - inode->i_size);
 108                         epos.offset -= adsize;
 109                         extent_trunc(inode, &epos, eloc, etype, elen, nelen);
 110                         epos.offset += adsize;
 111                         if (udf_next_aext(inode, &epos, &eloc, &elen, 1) != -1)
 112                                 printk(KERN_ERR "udf_truncate_tail_extent(): "
 113                                        "Extent after EOF in inode %u.\n",
 114                                        (unsigned)inode->i_ino);
 115                         break;
 116                 }
 117         }
 118         /* This inode entry is in-memory only and thus we don't have to mark
 119          * the inode dirty */
 120         UDF_I(inode)->i_lenExtents = inode->i_size;
 121         brelse(epos.bh);
 122 }
 123
 124 void udf_discard_prealloc(struct inode *inode)
 125 {
 126         struct extent_position epos = { NULL, 0, {0, 0} };
 127         kernel_lb_addr eloc;
 128         uint32_t elen;
 129         uint64_t lbcount = 0;
 130         int8_t etype = -1, netype;
 131         int adsize;
 132
 133         if (UDF_I(inode)->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB ||
 134             inode->i_size == UDF_I(inode)->i_lenExtents)
 135                 return;
 136
 137         if (UDF_I(inode)->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
 138                 adsize = sizeof(short_ad);
 139         else if (UDF_I(inode)->i_alloc_type == ICBTAG_FLAG_AD_LONG)
 140                 adsize = sizeof(long_ad);
 141         else
 142                 adsize = 0;
 143
 144         epos.block = UDF_I(inode)->i_location;
 145
 146         /* Find the last extent in the file */
 147         while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 1)) != -1) {
 148                 etype = netype;
 149                 lbcount += elen;
 150         }
 151         if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) {
 152                 epos.offset -= adsize;
 153                 lbcount -= elen;
 154                 extent_trunc(inode, &epos, eloc, etype, elen, 0);
 155                 if (!epos.bh) {
 156                         UDF_I(inode)->i_lenAlloc =
 157                                 epos.offset -
 158                                 udf_file_entry_alloc_offset(inode);
 159                         mark_inode_dirty(inode);
 160                 } else {
 161                         struct allocExtDesc *aed =
 162                                 (struct allocExtDesc *)(epos.bh->b_data);
 163                         aed->lengthAllocDescs =
 164                                 cpu_to_le32(epos.offset -
 165                                             sizeof(struct allocExtDesc));
 166                         if (!UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_STRICT) ||
 167                             UDF_SB(inode->i_sb)->s_udfrev >= 0x0201)
 168                                 udf_update_tag(epos.bh->b_data, epos.offset);
 169                         else
 170                                 udf_update_tag(epos.bh->b_data,
 171                                                sizeof(struct allocExtDesc));
 172                         mark_buffer_dirty_inode(epos.bh, inode);
 173                 }
 174         }
 175         /* This inode entry is in-memory only and thus we don't have to mark
 176          * the inode dirty */
 177         UDF_I(inode)->i_lenExtents = lbcount;
 178         brelse(epos.bh);
 179 }
 180
 181 void udf_truncate_extents(struct inode *inode)
 182 {
 183         struct extent_position epos;
 184         kernel_lb_addr eloc, neloc = {};
 185         uint32_t elen, nelen = 0, indirect_ext_len = 0, lenalloc;
 186         int8_t etype;
 187         struct super_block *sb = inode->i_sb;
 188         struct udf_sb_info *sbi = UDF_SB(sb);
 189         sector_t first_block = inode->i_size >> sb->s_blocksize_bits, offset;
 190         loff_t byte_offset;
 191         int adsize;
 192
 193         if (UDF_I(inode)->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
 194                 adsize = sizeof(short_ad);
 195         else if (UDF_I(inode)->i_alloc_type == ICBTAG_FLAG_AD_LONG)
 196                 adsize = sizeof(long_ad);
 197         else
 198                 BUG();
 199
 200         etype = inode_bmap(inode, first_block, &epos, &eloc, &elen, &offset);
 201         byte_offset = (offset << sb->s_blocksize_bits) +
 202                 (inode->i_size & (sb->s_blocksize - 1));
 203         if (etype != -1) {
 204                 epos.offset -= adsize;
 205                 extent_trunc(inode, &epos, eloc, etype, elen, byte_offset);
 206                 epos.offset += adsize;
 207                 if (byte_offset)
 208                         lenalloc = epos.offset;
 209                 else
 210                         lenalloc = epos.offset - adsize;
 211
 212                 if (!epos.bh)
 213                         lenalloc -= udf_file_entry_alloc_offset(inode);
 214                 else
 215                         lenalloc -= sizeof(struct allocExtDesc);
 216
 217                 while ((etype = udf_current_aext(inode, &epos, &eloc,
 218                                                  &elen, 0)) != -1) {
 219                         if (etype == (EXT_NEXT_EXTENT_ALLOCDECS >> 30)) {
 220                                 udf_write_aext(inode, &epos, neloc, nelen, 0);
 221                                 if (indirect_ext_len) {
 222                                         /* We managed to free all extents in the
 223                                          * indirect extent - free it too */
 224                                         if (!epos.bh)
 225                                                 BUG();
 226                                         udf_free_blocks(sb, inode, epos.block,
 227                                                         0, indirect_ext_len);
 228                                 } else {
 229                                         if (!epos.bh) {
 230                                                 UDF_I(inode)->i_lenAlloc =
 231                                                                 lenalloc;
 232                                                 mark_inode_dirty(inode);
 233                                         } else {
 234                                                 struct allocExtDesc *aed =
 235                                                         (struct allocExtDesc *)
 236                                                         (epos.bh->b_data);
 237                                                 int len =
 238                                                     sizeof(struct allocExtDesc);
 239
 240                                                 aed->lengthAllocDescs =
 241                                                     cpu_to_le32(lenalloc);
 242                                                 if (!UDF_QUERY_FLAG(sb,
 243                                                         UDF_FLAG_STRICT) ||
 244                                                     sbi->s_udfrev >= 0x0201)
 245                                                         len += lenalloc;
 246
 247                                                 udf_update_tag(epos.bh->b_data,
 248                                                                 len);
 249                                                 mark_buffer_dirty_inode(
 250                                                                 epos.bh, inode);
 251                                         }
 252                                 }
 253                                 brelse(epos.bh);
 254                                 epos.offset = sizeof(struct allocExtDesc);
 255                                 epos.block = eloc;
 256                                 epos.bh = udf_tread(sb,
 257                                                 udf_get_lb_pblock(sb, eloc, 0));
 258                                 if (elen)
 259                                         indirect_ext_len =
 260                                                 (elen + sb->s_blocksize - 1) >>
 261                                                 sb->s_blocksize_bits;
 262                                 else
 263                                         indirect_ext_len = 1;
 264                         } else {
 265                                 extent_trunc(inode, &epos, eloc, etype,
 266                                              elen, 0);
 267                                 epos.offset += adsize;
 268                         }
 269                 }
 270
 271                 if (indirect_ext_len) {
 272                         if (!epos.bh)
 273                                 BUG();
 274                         udf_free_blocks(sb, inode, epos.block, 0,
 275                                         indirect_ext_len);
 276                 } else {
 277                         if (!epos.bh) {
 278                                 UDF_I(inode)->i_lenAlloc = lenalloc;
 279                                 mark_inode_dirty(inode);
 280                         } else {
 281                                 struct allocExtDesc *aed =
 282                                     (struct allocExtDesc *)(epos.bh->b_data);
 283                                 aed->lengthAllocDescs = cpu_to_le32(lenalloc);
 284                                 if (!UDF_QUERY_FLAG(sb, UDF_FLAG_STRICT) ||
 285                                     sbi->s_udfrev >= 0x0201)
 286                                         udf_update_tag(epos.bh->b_data,
 287                                                 lenalloc +
 288                                                 sizeof(struct allocExtDesc));
 289                                 else
 290                                         udf_update_tag(epos.bh->b_data,
 291                                                 sizeof(struct allocExtDesc));
 292                                 mark_buffer_dirty_inode(epos.bh, inode);
 293                         }
 294                 }
 295         } else if (inode->i_size) {
 296                 if (byte_offset) {
 297                         kernel_long_ad extent;
 298
 299                         /*
 300                          *  OK, there is not extent covering inode->i_size and
 301                          *  no extent above inode->i_size => truncate is
 302                          *  extending the file by 'offset' blocks.
 303                          */
 304                         if ((!epos.bh &&
 305                              epos.offset ==
 306                                         udf_file_entry_alloc_offset(inode)) ||
 307                             (epos.bh && epos.offset ==
 308                                                 sizeof(struct allocExtDesc))) {
 309                                 /* File has no extents at all or has empty last
 310                                  * indirect extent! Create a fake extent... */
 311                                 extent.extLocation.logicalBlockNum = 0;
 312                                 extent.extLocation.partitionReferenceNum = 0;
 313                                 extent.extLength =
 314                                         EXT_NOT_RECORDED_NOT_ALLOCATED;
 315                         } else {
 316                                 epos.offset -= adsize;
 317                                 etype = udf_next_aext(inode, &epos,
 318                                                       &extent.extLocation,
 319                                                       &extent.extLength, 0);
 320                                 extent.extLength |= etype << 30;
 321                         }
 322                         udf_extend_file(inode, &epos, &extent,
 323                                         offset +
 324                                         ((inode->i_size &
 325                                                 (sb->s_blocksize - 1)) != 0));
 326                 }
 327         }
 328         UDF_I(inode)->i_lenExtents = inode->i_size;
 329
 330         brelse(epos.bh);
 331 }